10 



Mr. Chairman and Members of the Subcommittee: 



We appreciate the opportunity to discuss federal and state 

 efforts to address the problem of visibility Impairment in our 

 national parks and wilderness areas. While these areas are among 

 our greatest national treasures, an important part of our 

 enjoyment is the ability to see them clearly. Congress 

 recognized this in the Clean Air Act Amendments of 1977, when it 

 established a national goal of correcting and preventing 

 pollution that causes visibility impairment in the 158 large 

 national parks and wilderness areas, referred to as class I 

 areas. Seventeen years later, however, visitors to these areas 

 are not able to fully enjoy the spectacular views, such as those 

 at the Grand Canyon, that would exist in the absence of air 

 pollution. Haze caused by human activities often eliminates 

 important color distinctions and makes distant landscape features 

 difficult or impossible to see. According to the National Park 

 Service, some degree of visibility impairment caused by air 

 pollution occurs in every park that it manages, and visibility 

 degradation is a constant problem at some locations. 



We testified before this Subcommittee in March 1990 

 regarding the extent to which the Prevention of Significant 

 Deterioration (PSD) program was helping to protect air quality in 

 class I areas. 1 The PSD program was designed to ensure that the 

 construction of new facilities would not contribute to air 

 quality deterioration in areas where the air is already clean. 

 In our 1990 testimony, we noted that the program was doing little 

 to protect air quality in class I areas. Our testimony today 

 responds to your request that we determine whether there have 

 been improvements in the PSD program in the past 4 years and that 



1 Protecting Parks and Wilderness From Nearby Air Pollution Sources 

 (GAO/T-RCED-90-43, March 9, 1990) 



